DE-B 1090381 describes a method of covering pharmaceuticals with coating masses soluble in the stomach. These comprise a copolymer of 20 to 80% of at least one amino ester of (meth)acrylic acid and 80 to 20% of a monomer which forms a water-insoluble polymer as homopolymer. Specific examples of suitable polymerizable amino esters that are given are the esters of acrylic acid and (meth)acrylic acid with N,N-dimethylaminoethanol, N,N-diethylaminoethanol, N,N-dimethylaminopropanol and N-(hydroxyethyl)morpholine. Suitable co-monomers that are mentioned are lower esters of acrylic acid and preferably of (meth)acrylic acid, such as ethyl acrylate, methyl, butyl and hexyl (meth)acrylate. The preparation takes place by solution polymerization in an organic solvent; a working example is not given.
DE-B 1219175 describes a method of producing veterinary medicine active ingredient preparations which are protected against the effect of rumen juices of ruminants. For this, these preparations are coated with copolymers which comprise, in copolymerized form, N,N-dialkylaminoalkyl(meth)acrylamides and a co-monomer which is selected from (meth)acrylates, acrylonitrile and vinyl aromatics. Co-polymers based on N,N-dialkylaminoalkyl(meth)acrylates are regarded as disadvantageous according to the teaching of this document since the ester group, compared to amide group, rather saponifies in the basic medium.
DE-A 2135073 describes coating compositions for pharmaceuticals which comprise an aqueous polymer dispersion, where the polymer is composed to 10 to 55% by weight of monomers with a carboxyl group and/or aminoalkyl- or dialkylaminoalkylester group. A suitable monomer that is specified is, beside a large number of others, also diethylaminoethylmethacrylate (DEAEMA). Suitable co-monomers that are mentioned are the lower esters of (meth)acrylic acid, preferably methyl methacrylate, (meth)acrylonitrile, vinyl aromatics, vinylchloride and vinylacetate. The preparation takes place by aqueous emulsion polymerization, preferably by the emulsion feed method. Specific emulsion polymers based on DEAEMA are not disclosed.
For providing binders for pharmaceutical coatings with a low residual monomer content, DE-B 2512238 teaches the use of a powder obtained by spray-drying a polymer dispersion for producing coating solutions for these pharmaceuticals. As regards the dispersions used for the spray-drying, reference is made to DE 1090381, DE 1219175 and DE 2135073.
DE-A 2838278 describes coatings for oral administration forms for ruminants comprising a) at least one film-forming polymer with at least one basic amino group and with a nitrogen content of from 3 to 14% which is soluble in aqueous rumen medium at a pH above 5.5 within 24 hours, and b) at least one hydrophobic substance dispersed in the polymer which is selected from C12-C32-fatty acids, Al salts of these fatty acids and/or polycarboxylic acids.
To produce the coating, a solution in an organic solvent is used. A large number of nitrogen-containing homopolymers and copolymers is listed as suitable polymers, without discussing suitable processes for their preparation. Working example 29 here gives a copolymer of 40% N,N-diethylaminoethylmethacrylate, but without stating a process for its preparation.
GB 1324087 describes coating polymers for oral administration forms for ruminants which comprise a) at least one N,N-dialkylaminoalkyl(meth)acrylate and b) at least one ethylenically unsaturated compound which is selected from vinyl aromatics and derivatives thereof, vinyl esters, esters of (meth)acrylic acid and acrylonitrile in copolymerized form. Suitable monomers a) that are disclosed are N,N-dimethylaminoethylmethacrylate (DMAEMA) and tert-butylaminoethylmethacrylate (TBAEMA). As co-monomer b), in particular methylmethacrylate is considered to be unsuitable since it has a tendency to form excessively brittle coatings. Bulk polymerization, suspension polymerization, solution polymerization and emulsion polymerization are stated as suitable polymerization processes. The copolymers in the working examples were produced by solution polymerization.
DE 3426587 A1 describes a process for coating pharmaceutical forms by applying a film of a liquid, film-forming coating composition which comprises a dissolved polymer with pendant tertiary ammonium salt groups. To produce these polymer solutions, it is possible to convert, inter alia, copolymers based on N,N-dialkylaminoalkyl(meth)acrylates with aqueous inorganic or organic acids into aqueous ammonium salt solutions.
DE 3049179 A1 is an application of addition to DE 2512238 and relates to the use of a powder obtained by spray-drying in accordance with the teaching of the last-mentioned document in the form of an aqueous suspension which additionally comprises a plasticizing agent for producing coatings by thermal gelation.
EP 0058765 A2 describes coating compositions for pharmaceutical forms that are soluble or swellable in gastric juice which comprise, as binder, an emulsion polymer based on N,N-dialkylaminoalkyl(meth)acrylates, there being located between the amino group and the (meth)acrylate group a branched alkylene or aralkylene group having at least three carbon atoms arranged in a straight chain.
WO 2005/055986 and WO 2005/056619 describe polymers with pH-dependent swelling/dissolving behavior and their use in pharmaceutical forms.
WO 00/05307 deals with the provision of coatings and binders for pharmaceutical forms which comprise (meth)acrylate copolymers which have monomer radicals with tertiary amino groups, the aim being that simple dry or aqueous further processing be possible. For this, this document teaches a process in which (a) a copolymer of C1-C4 esters of (meth)acrylic acid and (meth)acrylate monomers which have tertiary ammonium groups, (b) a plasticizer and (c) an emulsifier with an HLB value of at least 14 are blended together, and the coating composition or binder is prepared there from by melting, pouring, spreading or spraying, where the copolymer (a) is introduced in powder form with an average particle size of from 1 to 40 μm. The processability achieved in this case is attributed to the provision of the copolymer (a) in powder form with an extremely small particle size.
WO 02/067906 relates to coatings and binders with improved water vapor permeability compared with those described in WO 00/05307. Here, the coatings and binders are prepared with a mixture which comprises (a) a copolymer of C1-C4 esters of (meth)acrylic acid and further (meth)acrylate monomers with functional tertiary ammonium groups in powder form with an average particle size of from 1 to 40 μm, (b) an emulsifier with an HLB value of at least 14 and (c) a C12-C18-monocarboxylic acid or a C12-C18-hydroxyl compound.
WO 2004/019918 describes coatings and binders which correspond in terms of their composition to those described in WO 00/05307 and WO 02/067906.
According to U.S. Pat. No. 6,696,085 B2, a methacrylic acid copolymer type C should be used as disintegrant. The methacrylic acid copolymer type C is an enteric polymer which is not soluble in the acidic pH range, but is water-soluble in the pH range of 7, as is present in the oral cavity. Besides a low fracture strength (<20N), the tablets have high friability (>7%) and include a high proportion, in the region of 15% by weight, of a coarsely particulate disintegrant. Consequently, they have low mechanical strength and, on account of the high proportion of coarsely particulate disintegrant, have an unpleasant sandy feel in the mouth.
The matrix components based on sugar alcohols, disintegrants and insoluble polymers are generally known for pharmaceutical applications from WO 2007/071581.
WO 2009/016258 discloses the preparation of aqueous polymer dispersions of cationic polymers based on N,N-diethylaminoethylmethacrylate as are used according to the invention, and their use for coating pharmaceuticals. This specification also describes the application of said polymers to ibuprofen pellets. However, it has turned out that these preparations are not storage-stable, become sticky upon storage, the taste masking deteriorates and the release is altered massively.